/Engine/Source/Runtime/Experimental/Chaos/Public/Chaos/GeometryParticlesfwd.h
namespace Chaos { [FArchive](API\Runtime\Core\Serialization\FArchive) & Chaos::operator<< ( [FArchive](API\Runtime\Core\Serialization\FArchive) & Ar, [FSpatialAccelerationIdx](API\Runtime\Chaos\Chaos\FSpatialAccelerationIdx) & Idx ) }